Shift time refers to the time interval between gear changes in a transmission. This interval is the time in which power delivery is transferred to the next selected gear, and engine speed is reduced or increased to synchronize the speed of the next gear. Shift time is usually in reference to motor vehicles, but can apply to any gearbox. Shift time is measured by the time it takes for the engine rpm to synchronize with the next gear input speed target. This is illustrated by ZF, describing the 100-300 millisecond shifts of their DCT transmissions.